DISTRIBUTORLESS Ignition System
The Distributorless Ignition System (DIS) uses the Engine Control Module (ECM) for determining ignition timing (spark advance). The ECM determines ignition timing (spark advance) based on various input signals. Following input signals may be used: engine coolant temperature, oxygen sensor, airflow meter, engine RPM, throttle position, vehicle speed sensor, park/neutral position switch, A/C switch, cranking (starter) signal and knock sensor.
Conventional distributor and pick-up coil have been replaced by a camshaft and crankshaft position sensor. Camshaft position sensor delivers input signals to terminals G22+ and G22- of ECM to indicate camshaft position. Crankshaft position sensor delivers input signal to terminals NE+ and NE- of ECM to indicate crankshaft position. The ECM detects the standard crankshaft position based on camshaft position sensor signals and the actual crankshaft position and engine speed by the crankshaft position sensor. Camshaft position sensor is located at flywheel end of front cylinder head, just below valve cover. See Figure. Crankshaft position sensor is located just above crankshaft pulley. See Figure.
The ECM uses 6 ignition primary control signals to ignitor for the ignition coils. See Fig 1. The ECM monitors IGF circuit at the ignitor to ensure ignition coils have fired. The ECM stops fuel injection as a fail-safe function when IGF reference signal has not been received.